One in eight cancer cases links to infections, new WHO analysis
Approximately one in eight new cancer cases diagnosed worldwide is caused by infections, according to a new analysis by the International Agency for Research on Cancer (IARC). In 2024, 2.3 million cases—representing 12% of the global total—were attributed to viruses, bacteria, or parasites. A significant proportion of these cancers can be prevented through vaccination, detecting and treating infections, and screening programs, reports News.ro.
Researchers analyzed data on 12 infectious agents known to cause cancer. The study, published online and set to appear in the October issue of The Lancet Oncology, provides the most up-to-date estimate of the global burden of infection-related cancers.
The highest number of cases was attributed to Helicobacter pylori, a bacterium that infects the stomach and can promote the development of gastric cancer. Approximately 760,000 cancer cases diagnosed in 2024 were linked to this infection.
Next is the human papillomavirus (HPV), associated with approximately 750,000 cases. HPV causes the majority of cervical cancer cases and is also implicated in anal, vulvar, vaginal, penile, and head and neck cancers.
Hepatitis B virus was responsible for approximately 360,000 cases—primarily liver cancer—while Epstein-Barr virus (EBV) accounted for about 260,000 cases. Hepatitis C virus was linked to another 160,000 cases. Together, these five infections caused nearly all the cancers attributed to infectious agents in this analysis.
Epstein-Barr virus: the fourth leading infectious cause of cancer worldwide
One key finding of the analysis is the magnitude of the cancer burden attributed to the Epstein-Barr virus. EBV is now the fourth leading infectious cause of cancer worldwide, ranking ahead of the hepatitis C virus.
The virus was already known to be linked to nasopharyngeal carcinoma and certain lymphomas. However, more recent evidence indicates that EBV also contributes to the development of a subset of gastric cancers.
The new analysis identifies 16 additional links between infections and various types of cancer compared to previous global estimates.
A large proportion of cases are preventable
The authors emphasize that effective prevention or treatment methods already exist for many of the infections responsible for this burden. These include vaccination against HPV and hepatitis B, the detection and treatment of H. pylori and viral hepatitis infections, the prevention and treatment of HIV, and cervical cancer screening.
There is currently no effective preventive vaccine for EBV; developing vaccines against this virus and other cancer-causing infectious agents is considered a research priority.
The burden is unevenly distributed worldwide.
More than three-quarters of infection-related cancers were diagnosed in low- and middle-income countries. East Asia accounted for 42% of global cases, primarily due to H. pylori and hepatitis B virus infections.
In the European Union, the burden of infection-related cancers is lower than the global average. According to the latest IARC estimates for the EU, approximately 144,000 cancer cases diagnosed in 2022—about 5% of the total—were attributed to major cancer-causing infections. The most significant were Helicobacter pylori and HPV infections, followed by hepatitis C and B viruses.
The study shows that preventing and treating cancer-causing infections is a key component of global cancer prevention.
